Abuja -Boko Haram is systematically killing men to assert its control and has seized yet another area in northern Nigeria, local media reported on Thursday.
Fleeing civilian residents said the sect began house-to-house sweeps in and around Bama, a Borno State town where Boko Haram fighters were clashing with soldiers.
Boko Haram captured and killed men suspected of being members of a civilian vigilante group that had resisted its advance, they said.
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"Everyone is a [Boko Haram] target as long as you are a male", said Senator Ahmed Zannah, who represents the central part of Borno State in the National Assembly.
More than 180 people have been killed and about 26 000 people forced to flee the Bama area in the past week, local newspaper Punch reported.
The National Emergency Management Agency registered 26 391 refugees from Bama.
Witnesses said Boko Haram was now in control of Bama, but the military has denied the reports.
The insurgents, meanwhile, captured several towns in the Gulani area of neighbouring Yobe State, according to The Nation newspaper.
Heavily armed Boko Haram fighters seized the council secretariat and the local government lodge in Bara, the area's key town, witnesses said.
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"The whole of my local government has been taken over", State House of Assembly representative Abdullahi Kukuwa was quoted as saying.
The insurgents were gathering large crowds to preach Islamic shariah law, Kukuwa said.
In August, Boko Haram declared a caliphate in the town of Gwoza, roughly 50km south of Bama.